RuleAnnotation

public enum RuleAnnotation : Hashable, CustomStringConvertible

An annotation that can be associated with any rule influencing how matches are interpretted and providing additional data about the token. The following annotations represent reserved words, but otherwise you can define any annotations you want.

  • .token Override the token to be created when the rule is matched (ignoring the Rule‘s produces property
  • ’.errorA specific error message to generate if theRule` is not satisfied
  • ‘.void’ The match should be completely ignored. This is not a failure but rather a consumption
  • ‘.transient’ The match should be made and a Node could be created but this token is not significant for the AST
  • ‘.pinned’ The token should be created with no value even if the Rule is not matched in an ignorable failure

  • Token to be created when the rule is matched

    Declaration

    Swift

    case token

  • An error to be generated when the rule is not matched

    Declaration

    Swift

    case error

  • Matches will be completely discarded (no node, no adoption of children by parent)

    Declaration

    Swift

    case void

  • Token will not be preserved in the AST but it’s children should be adopted by the parent node

    Declaration

    Swift

    case transient

  • Nodes will be created for failed optional matches

    Declaration

    Swift

    case pinned

  • The type of the token, used to inform code generation

    Declaration

    Swift

    case type

  • A custom developer defined annotation that your own AST will interpret

    Declaration

    Swift

    case custom(label: String)

  • The searchable hash value of the annotation

    Declaration

    Swift

    public var hashValue: Int { get }

  • Compares two annotations for equality (not values, but keys)

    Declaration

    Swift

    public static func == (lhs: RuleAnnotation, rhs: RuleAnnotation) -> Bool

    Parameters

    lhs

    The first annotation
    rhs

    The second annotation

    Return Value

    true if the annotations are the same, false otherwise.

  • A human readable description of the annotation

    Declaration

    Swift

    public var description: String { get }